Isolongifolene esters

ABSTRACT

NOVEL ISOLONGIFOLENE ESTERS OF THE FORMULA:   5-(R-COO-)-2,3,5,6,7,7A-HEXAHYDRO-2,7A-ETHANOINDENE   WHEREIN R IS A C1-C5 ALKYL GROUP ARE PREPARED BY ALLYLIC SUBTITUTION, E.G. OXIDATION, OF ISOLONGIFOLENE, FOLLOWED BY REPLACEMENT OF THE SUBSTITUENT BY AN RCO2- GROUP. SAID ESTERS HAVE VALUBLE PERFUMERY PROPERTIES PARTICULARLY AS REPLACEMENTS FOR VETIVEROL DERIVATIVES.

lvlal'd'l 7, 1972 I 0 A T ETIAL 3,647,841

ISOLONGIFOLENE ESTERS Filed Sept. 24, 1969 QOQ'Q g ombmggag WAV UNICAMSP 200 5000 4000 WAVE NUMBER Q o o R o m 8 a N 2 EDN V1 1 INS N VH1United States Patent C) US. Cl. 260 -489 2 Claims ABSTRACT OF THEDISCLOSURE Novel isolongifolene esters of the formula:

R-il-O wherein R is a C -C alkyl group are prepared by allylicsubstitution, e.g. oxidation, of isolongifolene, followed by replacementof the substituent by an RCO group. Said esters have valuable perfumeryproperties particularly as replacements for vetiverol derivatives.

This invention relates to perfumery compositions of the type where anumber of odoriferous materials, of synthetic or natural origin, areadmixed or compounded to form a perfumery concentrate. Such concentratesmay find use as such or after dilution, but more usually they are addedin small proportions to other materials, such as to space sprays or tosoap, detergent, cosmetic or deodorant compositions, or to substratessuch as fabrics, fibres or paper products, in order to provide them withagreeable olfactory properties. Thus such concentrates (as well as theaforesaid perfumed materials) are products of commerce and the perfumeryconcentrates may comprise a simple or complex mixture of individualperfumery compounds.

The sesquiterpane longifolene (I) is obtainable as a by-product in therefining of Indian oil of turpentine. It is known that it may beisomerised to isolongifolene (II) by a number of means, andisolongifolene may be subjected to controlled oxidation to yield amixture of ketones having valuable perfumery properties. It is alsoknown (see Tetrahedron Letters 8,417.424 (1964)) that one of theseketones, having the structure III may be reduced to give an epimericmixture of alcohols of the general structure IV.

3,647,847 Patented Mar. 7, 1972 We have now found methods of formingesters of alcohols of the type IV to produce a series of novel esterswhich have further been discovered to be highly suitable for use inperfumery.

Accordingly, from one aspect, this invention provides isolongifolenylcarboxylate esters of the structure Where R is an alkyl group having 1to 5 carbon atoms.

From a second aspect the invention provides compounded perfumerycompositions comprising an isolongifolenyl carboxylate ester of theinvention.

Longifolene may be isomerised to isolongifolene by methods known interpene chemistry, e.g. by treatment below C. with acetic acid oranother weak acid in the presence of a little sulphuric acid. or otherstrong protonating agent; or by the action of boron trifluorideetherate.

It has been found possible to prepare the novel esters fromisolongifolene by a variety of routes which can be considered as fallinginto two classes, which, however, have the common characteristic that ineach case a reactive substituent group is first introduced into thesecondary carbon atom in the position a to the olefinic double bond ofisolongifolene and by a further reaction or reactions the reactivesubstituent group is then replaced by a group of formula RC-O The firstof these, Class A, comprises first oxidising isolongifolene in acontrolled manner to produce a mixture comprising a ketone of theFormula III which is thereafter reduced to an alcohol of the Formula IV.This alcohol may then be esterified by known means to produce a novelester of the invention.

The controlled oxidation of isolongifolene to a mixture of ketones isdescribed for example in Tetrahedron 8, 42-48 (1960) and it may beaccomplished by the action of an acidic solution of a hexavalentchromium compound; e.g. by chromium trioxide in a mixture of tertiarybutanol, acetic acid and acetic anhydride; or by sodium dichromate insulphuric acid and acetic acid. Altematively, a mixture of vanadiumpentoxide and hydrogen peroxide in acetone might be used. Preferably thereaction mixture is maintained below 50 C. to prevent undueover-oxidation. Also the isomerisation and oxidation of longifolene isconveniently carried out without the isolation of the intermediateisolongifolene.

There are likewise a number of methods available for the reduction ofthe ketone III to the alcohol IV. Such methods will readily suggestthemselves to organic chemists; they include reduction with lithiumaluminium hydride as described in Tetrahedron Letters 8, 417-426 (1964),reduction with sodium borohydride in ethanol and Meerwein-Ponndorfreduction using aluminium isopropoxide in isopropanol. The alcohol 1Vmay then be esterified by known means such as by treatment with theappropriate carboxylic acid in the presence of a trace of acidiccatalyst such as sulphuric or hydrochloric acid or by treatment with theacid chloride or mixture of acid chloride and acid anhydride.

The second Class B, of possible routes from isolongifolene to the novelisolongifolenyl esters of the invention embraces a number of reactionsfor achieving this transformation, either directly or through theformation of other intermediates. For instance, isolongifolene may besubjected to allylic chlorination e.g. by reaction with chlorine in thepresence of sodium carbonate the resulting chloroisolongifolene thenbeing converted to the desired ester by replacement reaction, e.g. byreaction with the sodium salt of the appropriate carboxylic acid in thepresence of a tertiary amine such as triethylamine. Alternativelyisolongifolene may be treated with an organic peroin'de such astertAbutyl hydroperoxide, cumene hydroperoxide, di-tert-butyl peroxideor ter.-butyl-perbenzoate, in the presence of cuprous chloride and theappropriate carboxylic acid; or, where the acetate is required it may betreated with lead tetra-acetate or mercuric acetate, again in thepresence of the carboxylic acid, i.e. acetic acid. In all such reactionsit will generally be necessary simply to stir the reactants together foras long as is found necessary to produce the maximum or optimum yield.

The group R in the compounds of the invention is an alkyl groupcontaining from one to five carbon atoms. Appropriate carboxylic acidsfor use in the formation reactions mentioned therefore include acetic,propionic, butyric, pentanoic and hexoic acids. The preferred ester isthe acetate, that is where R is methyl.

It will, of course, be normally necessary to carny out a purificationprocedure after preparation of the novel esters and possibly also at oneor more intermediate stages in the case of Class A reaction sequence.Such procedures may vary according to the impurities involved but maygenerally comprise fractional distillation which has, in any case, beenfound a suitable method for effecting the final isolation andpurification of the isolongifolenyl esters.

The aforesaid esters for present uses have a distinctive woody odournote somewhat akin to the esters of vetiverol which are expensivematerials derived from vertiverol a constituent of vetivert oil.Accordingly, the compounded perfumery concentrates of the invention willoften be formulated to take maximum advantage of this note and besimilar to the formulations wherein the vertiverol esters have found useor would have found use if it had not been for their high price. Thus itis preferred that the esters be blended with one or more iononecompounds, such as the -,8 and a-ionOnes, the n-methylionones and/orisomethylionones; and/or with musk compounds, such as musk ketone orethylene brassylate, each of which may have been prepared syntheticallyor isolated from natural sources or used in combination with otheringredients in less refined extracts of natural origin.

The aforesaid esters will generally be used only in a small amount inperfumery compositions since even in such amounts the desirable woodynote is manifested. Thus the compounded perfumery compositions of theinvention will usually comprise from 0.1 to preferably 0.5 to 10%, byweight of the said esters based on the total weight of perfumeryingredients. However, the invention envisages the use of blends of theesters with at least one ionone and/or musk compound for subsequentincorporation into compounded perfumery compositions of more complexformulations. Indeed the perfumery compositions of the invention willoften comprise a considerable number of perfumery components. The blendsof the esters of the invention with ionone and/or musk compounds maycomprise, for example up to 60% by weight of the novel esters. Moreover,the novel esters have been found to blend particularly satisfactorilywith vertiveryl acetate, vetiverol, vetivert oil, sandalwood oil,cedarwood oil, labdanum oil, oakmoss oil and patchouli oil. Blends ofisolongifolenyl esters of the invention with any of these aforesaidcompounds are included within the scope of the invention.

The compounded perfumery compositions of the invention find use in awide variety of perfumed materials, for example, the compositions mayfind particular use in contourier-type perfumes, cologne or toiletwaters, space sprays or they can be blended in soap, detergent ordeodorant compositions including bath salts, shampoos, or in cosmeticpreparations, such as face creams, talcum powders, body lotions, suncream preparations and particularly, because of the nature of theirperfumery note, in male toilet products such as shave lotions andcreams. The compositions can also be used to perfume substrates such asfibres, fabrics and paper products.

The invention will now be illustrated by the following examples whereinall quantities are expressed on a weight basis. Examples 1-3 describesvarious methods of preparing the novel isolongifolenyl esters whilstExamples 4 to 6 describes novel perfumery compositions of the invention.

EXAMPLE 1 Isolongifolene (102 gms.), acetic acid (100 mls.) and cuprouschloride (0.2 gm), were introduced into a 500 ml. flask fitted with astirrer. The flask was heated to C. and 49 grams tert.-butyl perbenzoateadded over two hours. The mixture was heated at 80 C. or afurther 8hours and then diluted with petroleum ether and washed consecutivelywith water, sodium carbonate solution (10%) and water. The extract wasallowed to stand over anhydrous sodium sulphate over night and thepetroleum ether was removed by evaporation over a steam bath.Distillation of the oil yielded a mixture of isolongifolenyl acetateshaving an infra red spectrum as shown in FIG. I and the followingcharacterising data:

Refractive Index at 25 C.--1.5000 Density at 25 C.1.0l08 gs./cc. Boilingpoint at 2 mm. mercury pressure-ca. 131 C.

Saponification of 5 grams of the acetate mixture produced as above,using a solution of sodium hydroxide in aqueous ethanol, yielded 3 gramsof a mixture of alcohols having a refractive index of 1.5099 at 25 C.

EXAMPLE 2 Isolongifolene (204 'gms.) and anhydrous sodium oarbonate (80gms.) were placed in a 500 mls. flask fitted with a stirrer and coolingjacket. Chlorine was slowly passed into the mixture at such a rate thatthe temperature was maintained below 30 C. When the chlorination wasfinished the isolongifolenyl chlorides produced were filtered free fromthe inorganic salts.

The chlorides were then placed in a 2 l. flask fitted with a stirrer andwere heated with acetic acid (1.000 ml.) and sodium acetate (100 gms.)for 48 hours at 80 C.

The mixture was diluted with water and extracted with petroleum ether.The combined extracts were washed with water, sodium bicarbonatesolution 10%) and again with water. The resulting petroleum etherextract was then dried over anhydrous sodium sulphate and the solventremoved by evaporation over a steam bath. Distillation of the oilyielded a mixture of acetates as in Example 1.

EXAMPLE 3 Isolongifolene (750 mls.) and cuprous chloride (2 gms.) wereplaced in a 2 l. flask fitted with a stirrer. The flask was heated to C.A mixture of acetic acid gms.) and t.-butyl hydroperoxide (100 gms.) wasslowly added over 2 hours. The mixture was stirred for a further 16hours at 80 C. After cooling the oil was washed twice with water, oncewith 10% sodium carbonate and once with water. Distillation yieldedunchanged isolongifolene and a mixture of acetates, as in Example 1.

EXAMPLE 4 A Woody base suitable for incorporation into a wide variety ofperfumery compositions in concentrations ranging from 0.1% to 20% of thecompounded composition was prepared from the following ingredients:

Parts Cedarwood oil (American) 500 Isolongifolenyl acetate 200 OlibannmResin 50 Methyl ionone O Vetivert oil (Bourbon) Coumarin 20 Bois de RoseOil 10 Patchouli Oil (Penang) 10 Sandalwood Oil (East Indian) 10 EXAMPLE5 A spruce type fragrance suitable for use in a wide variety of perfumedmaterials, for example bath preparations, was prepared from thefollowing ingredients:

The last compound, ionone cyclic ether, is a benzopyran of the formulawherein the unsatisfied carbon valencies are filled by hydrogen atoms,according to the conventional nomenclature. These compounds may beprepared by isomerisation of p-ionone.

EXAMPLE 6 A modern perfume suitable for use in aldehyde soaps wasprepared from the following ingredients:

Parts Cinnamyl alcohol 150 Benzyl alcohol 100 Amyl salicylate 100 Benzylsalicylate 70 Methyl ionone 65 Amyl cinnamic aldehyde Isolongifolenylacetate 50 Phenyl ethyl alcohol 50 Hydroxycitronellal 50 Musk ketone 30Ver salide 3O P-isopropyl alpha methyl hydrocinnamic aldehyde 30Coumarin 20 Benzyl acetate 20 P-tert.-butylcyclohexyl acetate 20Vetivert oil (Bourbon) 20 Geranyl acetate 20 Civet (synthetic) l0 Decylalcohol 10 Lauryl alcohol 5 Lauryl aldehyde 2 Methyl nonyl acetaldehyde2 Decyl aldehyde 2 Iso-Jasmone 2 Methyl salicylate 2 Allyl caproate 2Methyl heptine carbonate 1 We claim: 1. A compound having the structure:

0 R-il-O wherein R is an alkyl group containing from 1 to 5 carbonatoms.

2. The compound according to claim 1 wherein R is methyl.

References Cited Chem. Abstracts, 49: 123863 60: 1617d, 62: 16305d.

JAMES A. PATIEN, Primary Examiner V. GARNER, Assistant Examiner US. Cl.X.R.

252522; 260-488 B, 497 R, 587, 631.5, 648 C, 675.5

